Differential Requirement of Oryza sativa RAR1 in Immune Receptor-Mediated Resistance of Rice to Magnaporthe oryzae

Abstract

The required for Mla12 resistance (RAR1) protein is essential for the plant immune response. In rice, a model monocot species, the function of Oryza sativa RAR1 (OsRAR1) has been little explored. In our current study, we characterized the response of a rice osrar1 T-DNA insertion mutant to infection by Magnaporthe oryzae, the causal agent of rice blast disease. osrar1 mutants displayed reduced resistance compared with wild type rice when inoculated with the normally virulent M. oryzae isolate PO6-6, indicating that OsRAR1 is required for an immune response to this pathogen. We also investigated the function of Os-RAR1 in the resistance mechanism mediated by the immune receptor genes Pib and Pi5 that encode nucleotide binding-leucine rich repeat (NB-LRR) proteins. We inoculated progeny from Pib/osrar1 and Pi5/osrar1 heterozygous plants with the avirulent M. oryzae isolates, race 007 and PO6-6, respectively. We found that only Pib-mediated resistance was compromised by the osrar1 mutation and that the introduction of the OsRAR1 cDNA into Pib/osrar1 rescued Pib-mediated resistance. These results indicate that OsRAR1 is required for Pib-mediated resistance but not Pi5-mediated resistance to M. oryzae.

The overexpression of OsACBP5 protects transgenic rice against necrotrophic, hemibiotrophic and biotrophic pathogens

“…RPM1 recognizes modifications of RIN4 followed by P. syringae infection in Arabidopsis and RPM1 interacts with RIN4 triggering RPM1-mediated immunity 102 . RAR1 and SGT1 conferred resistance against Xoo and M. oryzae when overexpressed in rice 103 , 104 . RAR1 forms a complex with the molecular chaperones HSP90 and SGT1 to initiate a signalling cascade in diverse plant immune responses 105 – 108 .…”

A Single-Nucleotide Polymorphism in the Promoter of a Hairpin RNA Contributes to Alternaria alternata Leaf Spot Resistance in Apple (Malus × domestica)

“…MILDEW8 (RPW8) are referred to as CC R -NB-LRRs (Grant et al, 2003;Chini et al, 2004a;Chini and Loake, 2005;Peart et al, 2005;Bonardi et al, 2011;Collier et al, 2011;Jupe et al, 2012;Arya et al, 2014a;Dong et al, 2016). Studies on the roles of TIR-NB-LRR and CC-NB-LRR proteins in plant defense initially focused on Arabidopsis thaliana and tobacco (Nicotiana tabacum) (Bent et al, 1994;Whitham et al, 1994) and were followed by extensive studies in barley (Hordeum vulgare), tomato (Solanum lycopersicum), potato (Solanum tuberosum), rice (Oryza sativa), wheat (Triticum aestivum), maize (Zea mays), and other crops (Milligan et al, 1998;Halterman et al, 2001;Jordan et al, 2011;Bai et al, 2012;Saunders et al, 2012;Cesari et al, 2013;Harris et al, 2013;Inoue et al, 2013;Song et al, 2013;Stirnweis et al, 2014;Sueldo et al, 2015;Wang et al, 2015Wang et al, , 2016. To date, two CC R -NB-LRR proteins have been characterized: Nicotiana benthamiana N REQUIREMENT GENE1 (NRG1) (Peart et al, 2005;Collier et al, 2011) and Arabidopsis ACTIVATED DISEASE RESISTANCE1 (ADR1) (Chini et al, 2004a;Chini and Loake, 2005;Bonardi et al, 2011;Collier et al, 2011).…”

Mutation of a Nucleotide-Binding Leucine-Rich Repeat Immune Receptor-Type Protein Disrupts Immunity to Bacterial Blight

“…RAR1 and RAC1 are other components that play a crucial role in both basal and some NLR-type R genemediated resistance (Ono et al, 2001;Thao et al, 2007;Wang et al, 2008;Kawano et al, 2010;Song et al, 2013). Similarly, knockdown of either RAR1 or RAC1 did not lead to the observed wed mutant phenotypes, suggesting that RAR1 and RAC1 are also not the downstream causal components of wed (Supplemental Fig.…”

“…1999; Muskett et al, 2002;Holt et al, 2005). In rice, RAR1 is reported to be involved in both PTI and some NLR gene-mediated race-specific resistance via the formation of a complex with Rac/Rop GTPase, OsRac1, and HSP90 (Ono et al, 2001;Thao et al, 2007;Wang et al, 2008;Kawano et al, 2010;Song et al, 2013). We therefore were interested in determining whether this complex is required for wed-mediated immune response.…”